Add support for Intel cache CPUID leafs

This exposes L1, L2, etc. cache sizes, cache line size, etc.

Across S/R, everything except cache line size can differ from the host. This is
because cache line size is critical for correct use of CLFLUSH / CLFLUSHOPT,
but as far as I know, the other cache parameters can only affect performance,
not correctness.

AMD uses different leafs for cache information, which are not yet supported.

fail. There are no known cases of cache line size other than 64 in the fleet.

PiperOrigin-RevId: 265544786

1 files changed, 7 insertions, 17 deletions

diff --git a/pkg/cpuid/cpuid_test.go b/pkg/cpuid/cpuid_test.go
index 6ae14d2da..a707ebb55 100644
--- a/pkg/cpuid/cpuid_test.go
+++ b/pkg/cpuid/cpuid_test.go
@@ -57,24 +57,13 @@ var justFPUandPAE = &FeatureSet{
 		X86FeaturePAE: true,
 	}}
 
-func TestIsSubset(t *testing.T) {
-	if !justFPU.IsSubset(justFPUandPAE) {
-		t.Errorf("Got %v is not subset of %v, want IsSubset being true", justFPU, justFPUandPAE)
+func TestSubtract(t *testing.T) {
+	if diff := justFPU.Subtract(justFPUandPAE); diff != nil {
+		t.Errorf("Got %v is not subset of %v, want diff (%v) to be nil", justFPU, justFPUandPAE, diff)
 	}
 
-	if justFPUandPAE.IsSubset(justFPU) {
-		t.Errorf("Got %v is a subset of %v, want IsSubset being false", justFPU, justFPUandPAE)
-	}
-}
-
-func TestTakeFeatureIntersection(t *testing.T) {
-	testFeatures := HostFeatureSet()
-	testFeatures.TakeFeatureIntersection(justFPU)
-	if !testFeatures.IsSubset(justFPU) {
-		t.Errorf("Got more features than expected after intersecting host features with justFPU: %v, want %v", testFeatures.Set, justFPU.Set)
-	}
-	if !testFeatures.HasFeature(X86FeatureFPU) {
-		t.Errorf("Got no features in testFeatures after intersecting, want %v", X86FeatureFPU)
+	if justFPUandPAE.Subtract(justFPU) == nil {
+		t.Errorf("Got %v is a subset of %v, want diff to be nil", justFPU, justFPUandPAE)
 	}
 }
 
@@ -83,7 +72,7 @@ func TestTakeFeatureIntersection(t *testing.T) {
 // if HostFeatureSet gives back junk bits.
 func TestHostFeatureSet(t *testing.T) {
 	hostFeatures := HostFeatureSet()
-	if !justFPUandPAE.IsSubset(hostFeatures) {
+	if justFPUandPAE.Subtract(hostFeatures) != nil {
 		t.Errorf("Got invalid feature set %v from HostFeatureSet()", hostFeatures)
 	}
 }
@@ -175,6 +164,7 @@ func TestEmulateIDBasicFeatures(t *testing.T) {
 	testFeatures := newEmptyFeatureSet()
 	testFeatures.Add(X86FeatureCLFSH)
 	testFeatures.Add(X86FeatureAVX)
+	testFeatures.CacheLine = 64
 
 	ax, bx, cx, dx := testFeatures.EmulateID(1, 0)
 	ECXAVXBit := uint32(1 << uint(X86FeatureAVX))